在代码底部运行的示例需要很长时间才能在我的机器上解决：

dumrat@dumrat:~/programming/python$ time python camels.py
[['F', 'F', 'F', 'G', 'B', 'B', 'B'], ['F', 'F', 'G', 'F', 'B', 'B', 'B'],
 ['F', 'F', 'B', 'F', 'G', 'B', 'B'], ['F', 'F', 'B', 'F', 'B', 'G', 'B'],
 ['F', 'F', 'B', 'G', 'B', 'F', 'B'], ['F', 'G', 'B', 'F', 'B', 'F', 'B'],
 ['G', 'F', 'B', 'F', 'B', 'F', 'B'], ['B', 'F', 'G', 'F', 'B', 'F', 'B'],
 ['B', 'F', 'B', 'F', 'G', 'F', 'B'], ['B', 'F', 'B', 'F', 'B', 'F', 'G'],
 ['B', 'F', 'B', 'F', 'B', 'G', 'F'], ['B', 'F', 'B', 'G', 'B', 'F', 'F'],
 ['B', 'G', 'B', 'F', 'B', 'F', 'F'], ['B', 'B', 'G', 'F', 'B', 'F', 'F'],
 ['B', 'B', 'B', 'F', 'G', 'F', 'F']]

real    0m20.883s
user    0m20.549s
sys    0m0.020s

这是代码：

import Queue

fCamel = 'F'
bCamel = 'B'
gap = 'G'

def solution(formation):
    return len([i for i in formation[formation.index(fCamel) + 1:]
                if i == bCamel]) == 0

def heuristic(formation):
    fCamels, score = 0, 0
    for i in formation:
        if i == fCamel:
            fCamels += 1;
        elif i == bCamel:
            score += fCamels;
        else:
            pass
    return score

def getneighbors (formation):
    igap = formation.index(gap)
    res = []
    # AB_CD --> A_BCD | ABC_D | B_ACD | ABD_C
    def genn(i,j):
        temp = list(formation)
        temp[i], temp[j] = temp[j], temp[i]
        res.append(temp)

    if(igap > 0):
        genn(igap, igap-1)
    if(igap > 1):
        genn(igap, igap-2)
    if igap < len(formation) - 1:
        genn(igap, igap+1)
    if igap < len(formation) - 2:
        genn(igap, igap+2)

    return res

class node:
    def __init__(self, a, g, p):
        self.arrangement = a
        self.g = g
        self.parent = p

def astar (formation, heuristicf, solutionf, genneighbors):

    openlist = Queue.PriorityQueue()
    openlist.put((heuristicf(formation), node(formation, 0, None)))
    closedlist = []

    while 1:
        try:
            f, current = openlist.get()
        except IndexError:
            current = None

        if current is None:
            print "No solution found"
            return None;

        if solutionf(current.arrangement):
            path = []
            cp = current
            while cp != None:
                path.append(cp.arrangement)
                cp = cp.parent
            path.reverse()
            return path

        #arr = current.arrangement
        closedlist.append(current)
        neighbors = genneighbors(current.arrangement)

        for neighbor in neighbors:
            if neighbor in closedlist:
                pass
            else:
                openlist.put((current.g + heuristicf(neighbor),
                             node(neighbor, current.g + 1, current)))

        #sorted(openlist, cmp = lambda x, y : x.f > y.f)

def solve(formation):
    return astar(formation, heuristic, solution, getneighbors)

print solve([fCamel, fCamel, fCamel, gap, bCamel, bCamel, bCamel])
#print solve([fCamel, fCamel, fCamel, fCamel, gap, bCamel, bCamel, bCamel, bCamel])

每只只供三只骆驼。我想至少这样做4次。该测试用例仍在运行（现在:(）已经大约5分钟了。如果完成，我将对其进行更新。

我应该怎么做才能改善这段代码？（通常以性能为依据，但也欢迎其他建议）。